#include <iostream>
#include <algorithm>

using namespace std;

typedef long long LL;

const int N = 2e5 + 10;
int n,c;
LL a[N];


int main()
{
    cin >> n >> c;
    for(int i = 1;i <= n;i++)
    {
        cin >> a[i];
    }
    sort(a + 1, a + 1 + n);
    LL ret = 0;
    for(int i = 2;i <= n;i++)
    {
        LL b = a[i] - c;
        ret += upper_bound(a + 1, a + i,b) - lower_bound(a + 1,a + i,b);
    }
    cout << ret << endl;
    return 0;
}